MANUAL PHYSIOLOGY PRACTICAL - Repository:The Medical ...

FM/UOJ
A pointer moves in an ark by operating a wheel at the back. This pointer travels
from the mark at the centre up to the vertical plane of the tested eye. The movement of
the pointer is coupled to a pin at the back of the instrument. A paper is fitted to the paper
holder and the position of the moving pin can be entered on the paper by pressing the
paper holder against it. The whole assembly could be rotated through full circle the fields
of vision at every angle could be detected accurately.
Method:
Take the perimeter chart and fix it on to its holder, so that the marks on the holder
correspond to the marks on the chart. Move the pointer to the mark (bring the pin to the
centre) and press the paper against the pin to make sure that the centre of the chart
corresponds to the centre of the holder.
Seat the subject comfortably and cover one eye. Position the chin on its stand so
that the eye to be examined is against the central mark on the perimeter. Instruct the
subject to fix the gaze on the mark and indicate when the pointer comes into view. Take
the pointer to the outer most point by rotating the wheel and move it slowly towards the
centre. As soon as the subject gives the signal, stop the wheel and press the paper holder
against the pin to get the position entered in the chart. Rotate the arc by 30° and repeat the
procedure. Record the field of vision until the circle is completed.
Remove the chart and fit it again to test the other eye and carry out the procedure
for the other eye. Remove the paper and join the points made by the pin to obtain the field
of vision.
Past a copy of the Perimeter chart.
Give examples of change in visual field:
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Neurology
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